Ligand-Gated Ion Channels

The function of these receptors is to regulate flow of ions into and out of cells. GABA AND ACETYLCHOLINE

G Protein–Coupled Receptor Systems

G protein–coupled receptor systems have three components: the receptor itself, G protein (so named because it binds guanosine triphosphate [GTP]), and an effector (typically an ion channel or an enzyme).

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Transcription factors

differ from other receptors in two ways: (1) transcription factors are found within the cell rather than on the surface, and (2) responses to activation of these receptors are delayed

Ex - Steriods and thyroid hormones

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What is the function of transcription factors?

regulate protein synthesis

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affinity

refers to the strength of the attraction between a drug and its receptor** Drugs with high affinity are strongly attracted to their receptors **

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intrinsic activity

the ability of a drug to activate a receptor upon binding

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The intrinsic activity of a drug is reflected in its ________

maximal efficacy

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an antagonist is a drug with affinity for a receptor but with no ______

intrinsic activity

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A partial agonist is an agonist that has only moderate

intrinsic activity ex- Pentazocine(Talwin) a narcotic

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The therapeutic index is defined as ______

the ratio of a drug's LD50 to its ED50.

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The therapeutic index is a measure of

a drug's safety.

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The ED50 is defined as ____

the dose that is required to produce a defined therapeutic response in 50% of the population